A series of porous carbon samples as electric double layer capacitor electrode materials were prepared by a pyrolysis process using phenol formaldehyde resin (PF) as precursors and KOH/ZnCl2 as activation agents. Porous carbon samples were characterized by thermogravimetric analysis, X ray diffraction, nitrogen adsorption/desorption isotherms and transmission electron microscopy. The results showed that the KOH/ZnCl2/PF mass mixing ratio and activation temperature had a remarkable effect on the porosity, the specific surface area and the pore size of the carbons. The prepared carbon material PC-6 exhibits a high specific capacitance of 141.56 F/g and a average specific energy of 74.13 Wh/kg at a current density of 120 mA/g in the electrolyte of 1 M Et3MeNBF4/PC, and the average specific energy still remained 49.48 Wh/kg even at a high current density of 2000 mA/g. The excellent electrochemical behavior of PC-6 can be attributed to the highly development pore structure. (C) 2012 Elsevier B. V. All rights reserved.